Fighting Gardening Misinformation

The misinformation about gardening on the internet appears to be getting worse.

That’s probably true of just about every subject, but I have recently come across some gardening tidbits that are beyond the pale. I won’t dignify them by linking to them (google the key words, you’re sure to find the pages if you really want to), but here’s a sample of some I’ve come across just in the last 24 hours:

Bad Information

  • Plant dill with tomatoes and tomato hornworms will eat the dill instead of the tomatoes.
  • Bees love the flowers of stinging nettle, so leave them in your garden to attract them.
  • Glue pennies to a sphere (like a bowling ball) and put near your hydrangeas to make them blue.
  • Make your own weed killer out of regular grocery store vinegar, salt, and dish soap.
  • Pyrethrum is a safe, organic pest control that is non-toxic to humans and animals.

Use battery acid to acidify your soil. You can just pour it right on and irrigate the next day. Or, you can put it in a garbage can, mix with water, and then dump it on. No mentions of quantity or demonstrated need, no – just throw that stuff right in your garden.

Stupid Information

So those first three are just stupid*, but those last two are downright dangerous. Pyrethrum is extremely toxic to bees. If you haven’t heard lately, bees need all the help they can get to continue providing the valuable service of pollination. Pinterest users have pinned the article, “Extensive list of organic pest control remedies”, which listed this “fact”, dozens of times. In the original article, the author accompanied the suggestion with the words, “harmless to humans and animals.”

Consider the context. It’s nestled among completely ineffective suggestions like steeping onion peels in water for a pesticide. The article also suggests brewing up a batch of the well-intentioned but completely ridiculous “bug juice”. The bug juice consists of large quantities of the pest insect blended with water and sprayed on susceptible plants. This context implies benignity that absolutely does not exist for this chemical. This is despite the fact that it is plant-derived and hence “organic.”

And as for the sulfuric acid, how could ANYONE think for even a second that battery acid is safe to apply to the soil? If you were to pick up a tub of it, the numerous warnings ought to alert you that you shouldn’t even be handling it, much less throwing it around your garden. Adding acid to your soil does not suddenly make it more acid – soil pH is the result of weathering and long-term chemical processes. There is no fast fix to soil pH problems, and anyway, no one should even think about messing with their soil pH without an actual laboratory soil test verifying a pH issue (in which case the lab will make a recommendation for remedying the problem, and it will NOT involve willy-nilly application of a highly corrosive chemical).

Do your research

Break the chain, my fellow gardeners, please. If you find an idea that appeals to you and it is on a site that makes liberal use of the words, “thrifty,” “moms,” “natural,” or “organic”; if it comes from TipNut, eHow, AllExperts, Yahoo Voices, or any such site, don’t take it as gospel truth.

Do your research before pinning these ideas to Pinterest, or tweeting them, or mentioning them in passing to a friend. Verify them from numerous sources, ideally adding a “” or “” operator to your searches. These search operators find resources from a university or organization that will hopefully be reliable and authoritative. However, I have seen some pretty shocking stuff on these sites lately too – not everything is edited and fact-checked.

If you cannot verify them, they are opinion, and most likely a misinformed opinion. These are often created by someone who fancies themselves an expert. Be careful out there and help others be careful as well.

See, look, research works!


*Why are these ideas stupid? Tomato hornworms only eat tomatoes and related plants like tobacco – they wouldn’t and couldn’t consume dill. The wind pollinates stinging nettle. If a bee landed on it, it was probably only to take a rest, as its flowers would not even be recognizable as such to bees.

Pennies will never, ever turn a hydrangea blue – it is the presence of aluminum in soil that affects this change, and pennies do not contain aluminum (except the 1.5 million aluminum pennies which were minted in 1974, but those never circulated, and it is technically illegal to possess them).

The make-your-own weed killer recipe is ineffective with household vinegar, and if you need to kill weeds in concrete, as the recipe suggests it should be used for, you are better off using boiling water or a weeding knife (even an old butter knife), both of which are easier and cheaper than mixing up a batch of this.

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